(Press-News.org) A newly developed timeline of early animal fossils reveals a link between sea levels, changes in marine oxygen, and the appearance of the earliest ancestors of present-day animals.
The study reveals clues into the forces that drove the evolution of the earliest organisms, from which all major animal groups descended.
A team from the University of Edinburgh studied a compilation of rocks and fossils from the so-called Ediacaran-Cambrian interval – a slice of time 580–510 million years ago. This period witnessed an explosion of biodiversity according to fossil records, the causes of which have baffled scientists since Charles Darwin.
The early animals found from this era were all sea-dwellers, at a time when oxygen levels in the air and ocean were much lower than today.
While the very first lifeforms before this time were mostly single-cell, and simple multi-celled organisms, creatures in the Ediacaran Period started to become more complex, with multiple cells organised into body plans that allowed them to feed, reproduce, and move across the ocean floor.
This era also marked the emergence of so-called bilaterian animals – which display symmetrical body plans, in common with most present-day species including humans.
By compiling data from different sources – including radioactive dating and geochemical information about the layers of rock in which fossils were found – the team mapped all major fossil finds and various environmental datasets onto a single timeline.
The new chronology allowed the team to study trends in biodiversity for the period in question with more detail than before.
They combined these insights with further chemical clues from the geological record – confirming a link between major changes in global sea levels, intervals when shallow marine environments gained more oxygen, and the appearance and diversification of early animal groups.
This dynamic set the stage for several significant bursts in biological diversity, known as the Avalon, White Sea, and Cambrian assemblages, each marking the arrival of new animal groups and the decline of others.
By reconstructing environmental conditions in deepest time, the study unlocks new insights into the ancient forces and pressures that shaped the earliest life on our planet.
The team also identified gaps in the fossil record, suggesting that current knowledge about early animals is biased by the clusters of sites worldwide where fossils have been found and studied.
Dr Fred Bowyer of the University of Edinburgh’s School of Geosciences, said: “Constructing a timescale of early animal evolution using the rock record is a daunting task, only made possible through international and interdisciplinary research. But an integrated global approach is crucial. It exposes biases in our records, while also revealing patterns in fossil appearances, sea level cycles, and environmental oxygen."
Mariana Yilales Agelvis, a PhD student in the School of Geosciences who co-authored the study, said: “Knowing what drives biodiversity is a fundamental piece of knowledge in the puzzle of life. I feel very privileged to have built upon decades of interdisciplinary global research, and contributed to a better understanding of the role that sea level plays in early animal evolution.”
The paper was published in Science Advances and funded by the Natural Environment Research Council (NERC).
END
Sea level changes shaped early life on Earth, fossil study reveals
2024-08-02
[Attachments] See images for this press release:
ELSE PRESS RELEASES FROM THIS DATE:
'Screaming Woman' mummy may have died in agony 3,500 years ago
2024-08-02
In 1935, the Metropolitan Museum of New York led an archaeological expedition to Egypt. In Deir Elbahari near Luxor, the site of ancient Thebes, they excavated the tomb of Senmut, the architect and overseer of royal works – and reputedly, lover – of the famed queen Hatschepsut (1479-1458 BCE). Beneath Senmut's tomb, they found a separate burial chamber for his mother Hat-Nufer and other, unidentified relatives.
Here, they made an uncanny discovery: a wooden coffin holding the mummy of an elderly woman, wearing a black wig and two scarab rings in silver and gold. But what struck the archaeologists was the ...
Healthy AI: Sustainable artificial intelligence for healthcare
2024-08-02
Similar to other sectors around the world, the light speed development of artificial intelligence (AI) has made its way into healthcare, particularly the radiology field. As such, AI-based diagnostic systems are flourishing, with hospitals quickly adopting the technology to assist radiologists. In contrast, there are concerns about the environmental impact of increasingly complex AI models and the need for more sustainable AI solutions.
Therefore, Associate Professor Daiju Ueda of Osaka Metropolitan University’s ...
First full 2-D spectral image of aurora borealis from a hyperspectral camera
2024-08-02
Auroras are natural luminous phenomena caused by the interaction of electrons falling from the sky and the upper atmosphere. Most of the observed light consists of emission lines of neutral or ionized nitrogen and oxygen atoms and molecular emission bands, and the color is determined by the transition energy levels, molecular vibrations and rotations. There is a variety of characteristic colors of auroras, such as green and red, but there are multiple theories about the emission process by which they appear in different types of auroras, and to understand the colors of auroras, the light must be broken down. ...
Turkey vultures fly faster to defy thin air
2024-08-02
Mountain hikes are invigorating. Crisp air and clear views can refresh the soul, but thin air presents an additional challenge for high-altitude birds. ‘All else being equal, bird wings produce less lift in low density air’, says Jonathan Rader from the University of North Carolina (UNC) at Chapel Hill, USA, making it more difficult to remain aloft. Yet this doesn’t seem to put them off. Bar-headed geese, cranes and bar-tailed godwits have recorded altitude records of 6000 m and more. So how do they manage to take to the air when thin air offers ...
Texas A&M professor named to Committee on Rural Health by U.S. Secretary of Health and Human Services
2024-08-01
Dr. Alva O. Ferdinand, head of the Department of Health Policy and Management at the Texas A&M University School of Public Health, has been named to the Health Resources and Services Administration’s National Advisory Committee on Rural Health by U.S. Secretary of Health and Human Services Xavier Becerra. She will serve a four-year term on the committee, which is comprised of nationally recognized rural health experts tasked with providing recommendations on rural health issues.
Since 2019, Ferdinand has served as director of the Southwest Rural Health Research Center, whose research has impacted federal policies nationwide for more than two decades. ...
Drug developed for pancreatic cancer shows promise against most aggressive form of medulloblastoma
2024-08-01
A drug that was developed to treat pancreatic cancer has now been shown to increase symptom-free survival in preclinical medulloblastoma models – all without showing signs of toxicity.
Medulloblastoma is the most common malignant brain tumor in children. Survival rates vary according to which one of the four subtypes a patient has, but the worst survival rates, historically at about 40%, are for Group 3, which this research focused on.
Jezabel Rodriguez Blanco, Ph.D., an assistant professor who holds dual appointments at MUSC Hollings Cancer Center and the Darby Children’s ...
Retreat of tropical glaciers foreshadows changing climate's effect on the global ice
2024-08-01
MADISON — As they are in many places around the globe, glaciers perched high in the Andes Mountains are shrinking. Now, researchers at the University of Wisconsin–Madison and their collaborators have uncovered evidence that the high-altitude tropical ice fields are likely smaller than they've been at any time since the last ice age ended 11,700 years ago.
That would make the tropical Andes the first region in the world known to pass that threshold as a result of the steadily warming global climate. It also makes them possible harbingers of what's to come for glaciers globally.
"We think these are the canary ...
St. Jude gene panel for pediatric cancers increases access to high-quality testing
2024-08-01
Scientists at St. Jude Children’s Research Hospital have created a panel that is able to provide a diagnosis for >90% of pediatric cancer patients by sequencing 0.15% of the human genome. The panel is a cost-effective way to test and classify childhood malignancies and to help guide patient treatment. The panel’s performance and validation were published this week in Clinical Cancer Research.
Finding the mutations in a child’s cancer with powerful sequencing technology can lead to better outcomes. Physicians use that knowledge to tailor targeted treatments to the specific cancer-causing mutations affecting each patient. However, current ...
Health insurers have required prior authorization for services for decades—but have they treated patients equitably?
2024-08-01
Prior authorization—the process by which a health insurance company denies or approves coverage for a health care service before the service is performed—became standard practice beginning with Medicare and Medicaid legislation in the 1960s.
Although research has uncovered disparities in prior coverage for cancer patients based on race, little has been known to date on the role of prior authorization in increasing or decreasing these disparities.
To learn more about the issue, Benjamin Ukert, PhD, an assistant professor of health policy and management in the Texas A&M ...
Trying to limit calories? Skip the dip, researchers advise
2024-08-01
UNIVERSITY PARK, Pa. — Snacks provide, on average, about one-fourth of most people’s daily calories. With nearly one in three adults in the United States overweight and more than two in five with obesity, according to the National Institutes of Health, researchers in the Penn State Sensory Evaluation Center are investigating how Americans can snack smarter.
The latest study conducted in the center, housed in the College of Agricultural Sciences, investigated how eating behavior changes when consumers are served a dip with a salty snack. The findings, available online now and to be published in the November issue ...